DNA methylation is a process where methyl groups are added to specific locations on the DNA molecule, typically at cytosine-guanine (CpG) dinucleotides. This chemical modification can influence gene expression without altering the underlying DNA sequence.

In the podcast episodes provided, DNA methylation is explored in the context of its role in cancer detection, cellular identity, and the biology of aging. The episodes highlight how changes in DNA methylation patterns can be used as biomarkers for early cancer detection through liquid biopsies, and how cellular reprogramming techniques may have the potential to reverse aging-related changes in DNA methylation.

The importance of DNA methylation and its regulation of gene expression is a central topic in "6-Step Protocol To Stop Decline, Stay Young & Reverse Aging After 40+" and "#290 - Liquid biopsies for early cancer detection, the role of epigenetics in aging, and the future of aging research".